Fuel supply system



Nov. 1, 1960 E. A. HAASE FUEL SUPPLY SYSTEM Filed Sept. 28, 1959 1N VENTOR. A. HAASE ELMER United States Patent FUEL SUPPLY SYSTEM Elmer A. Haase, South Bend, Ind., assignor to The Bendix Corporation, a corporation of Delaware Filed Sept. 28,1959, Ser. No. 842,733

4 Claims. (Cl. 123-119) The present invention relates to a fuel supply system for supplying metered fuel to the induction passage of an internal combustion engine.

The fuel supply system of the present invention is particularly adapted for use on an aircraft engine but is not limited to use on such engines.

It is an object of the present invention to provide a fuel supply system for injecting fuel under pressure into the induction passage of an internal combustion engine wherein a relatively inexpensive diaphragm type fuel pump may be utilized.

It is a further object of the present invention to provide for an internal combustion engine a fuel supply system which is reliable in operation and which incorporates manually operated means for adjusting the metered fuel flow as desired during the operation of the engine.

These and other objects and advantages of the present invention will become readily apparent from the following detailed description taken in connection with the appended drawing wherein the single figure is a schematic view of a fuel supply system embodying the present invention.

Referring now to the figure, numeral designates a fuel supply system having a fuel pump 12, an air pump 14, metering controls 16, flow divider 18 and a metered fuel pressure gauge 20. A plurality of discharge conduits 22 emanate from flow divider 18 and terminate with respective connections to discharge nozzles 24 which are adapted to be mounted in the induction passage of the internal combustion engine to which the fuel supply system is adapted to supply fuel. A portion of the internal combustion engine is shown at 26 together with a portion of the induction passage 28 in which is mounted a throttle 30. Conveniently the nozzles 24 are mounted in the in duction passage 28 adjacent each of the inlet valves (not shown) of engine 26. It is to be understood, however, that the number of nozzles and their location may be varied as desired.

The interior of fuel pump 12 is divided into an air chamber 32 and a fuel chamber 34 by diaphragm or movable wall 36. Fuel chamber 34 is provided with an inlet 38 which is adaptedly connected to a source of fuel by an appropriate conduit (not shown). A check valve 40 is provided in inlet 38 to prevent reverse flow therethrough. Fuel chamber 34 is also provided with an outlet 42 having a check valve 44. A conduit 46 connects outlet 42 to the metering control 16. An actuating rod 48 is secured to the central portion of the diaphragm 36 and projects exteriorly of fuel pump 12 where said rod is formed with a reduced diameter stem 50 and an enlarged head 52. A rocker arm 54 is provided with a hole 56 to receive a stem 50. In assembly, the stem 50 is inserted through the hole 56 and the enlarged head 52 formed by peeniug over the end of stem 50 to form the enlarged head 52. The assembly is such that actuating rod 48 has a one-way connection with rocker arm 54 such as when rocker arm is actuated by the engine driven cam 58 rod 48 is raised to move diaphragm 36 in a fuel intake direc- 2,958,321 Patented Nov. 1, 1960 2 tion. A spring 60 is mounted in air chamber 32 to urge diaphragm 36 downwardly in a fuel discharge direction.

Air pump 14 is provided with a pumping chamber 62, one wall of which is formed by a diaphragm or movable wall 64. An air pump actuating rod 66 is secured to the central portion of the diaphragm 64 and is connected through one-way connection 68 with rocker arm 54. The connection between air pump actuating rod 66 and rocker arm 54 is such that the rocker arm urges diaphragm 64 in an air discharge direction conjointly with movement of the fuel pump diaphragm 36 in a fuel intake direction. A spring 70 is mounted in chamber 62 to urge diaphragm 64 in air intake direction. Air pumping chamber 62 is provided with an inlet 72 controlled by a check valve 74 and with an outlet 76 which is controlled by a check valve '78. A passage 80 connects air pump outlet 76 to the air chamber 32 of fuel pump 12. Air chamber 32 is provided with a calibrated vent 82 to permit air in the chamber to escape to the atmosphere.

Fuel from conduit 46 passes through a metering restriction 84 in metering control 16. The area of metering restriction 84 is controlled by a valve 86 which is operatively connected to throttle 30 by means of links 88, 90 and 92. Metered fuel from restriction 84 is connected by means of conduits 94 and 96 to a chamber 98 in flow divider 18. A by-pass passage 100 is connected at one end to the source of fuel (not shown) and at the other end to a restriction 102 which opens into conduit 94. The area of restriction 102 is controlled by a valve 104 which is positioned by a manually actuable lever 106.

Flow divider 18 is provided with chambers 108 and 110 which are separated 'by a diaphragm or movable wall 112. Chamber 108 is vented to the atmosphere through port 114. Chamber 110 is connected to chamber 98 by means of conduit 116. Fuel from chamber 98 passes through restriction 118 into a flow divider chamber 120 and thence through a plurality of calibrated orifices 122 into discharge conduits 22. A valve 124 is secured to the central portion of diaphragm 112 and is disposed to vary the area of restriction 118. A calibrated spring 126 is located in chamber 108 to urge diaphragm 112 and valve 124 downwardly to close restriction 118. A pressure gauge 20 is connected to flow divider chamber 120 by means of conduit 128. Pressure gauge 20 may be calibrated to show metered fuel pressure or fuel flow in pounds or gallons per hour.

In operation, air pump 14 discharges air at a pressure which varies as a function of engine speed. The air pressure from air pump 14 is conducted via conduit 80 to air chamber 32 to fuel pump 12 wherein the air pressure acts on diaphragm 36 to urge the diaphragm downwardly in a fuel discharge direction. The pressure of the fuel discharged from outlet 42 will vary directly with the air pressure applied to diaphragm 36 and thus the fuel discharged through outlet 42 will be at a pressure which varies in accordance with engine speed.

Fuel discharge by fuel pump 12 passes to the metering controls 16 wherein the fuel is metered as a function of throttle position by means of valve 86. The metered fuel in conduit 94 may be further controlled to provide compensation for load or ambient air conditions or other factors affecting engine operation by means of the by-pass valve 104. In a preferred embodiment the operator adjusts valve 104 to give the desired reading on gauge 20 for the particular engine operating conditions encountered. It is to be understood, however, that various automatic devices to compensate for changes in altitude, engine load etc. may be connected to lever 1116.

The spring 126 and flow divider 18 is calibrated to permit valve 124 to open when a predetermined fuel pressure has been reached in conduit 96. The fuel pressure in conduit 96 is transmitted via conduit 116 to chamber 110 to act on the underside of diaphragm 112 to oppose spring 126. With valve 124 opened, fuel passes into the flow divide-r chamber 120 where it is divided equally among the discharge conduits 22 for discharge into'the induction passage 28 through nozzles 24. In a preferred embodiment the nozzles 24 are of the type disclosed and claimed in my copending application Serial No. 834,705 riled August 19, 1959 and now abandoned.

The fuel supply system of the present invention is particularly advantageous where low cost is an important item since only one fuel pump is required and that pump may be of relatively inexpensive construction. Furthermore, the fuel supply system may readily incorporate a pressure gauge which may be used to give an accurate fuel flow setting to the metering control. The fuel supply system has a minimum number of parts and only a few of those require a high degree of accuracy in their construction. Furthermore, the fuel supply system is constructed so as to be relatively insensitive to normal dirt and impurities encountered in normal operation.

Although only one embodiment of my invention has been described in detail it will be readily apparent to those skilled in the art that other changes, modifications and arrangements of parts may be made without departing from the spirit of my invention.

I claim:

1. A fuel supply system for an internal combustion engine having a source of fuel and an induction passage with a throttle mounted therein comprising an engine driven air pump having an outlet, an engine driven diaphragm type fuel pump having an outlet, means connecting said source of fuel to said fuel pump on one side of said diaphragm, means connecting the air pump outlet to said fuel pump on the opposite side of said diaphragm whereby the pressure of the fuel discharged from the fuel pump outlet is a function of the air pressure acting on said diaphragm, conduit means connecting said fuel pump outlet to said induction passage, valve means in said conduit connected to said throttle to vary the effectime allow area of said conduit in response to throttle movement, a by-pass passage connecting said conduit downstream of said valve to a source of pressure lower than the pressure in said conduit, and a valve in said passage for controlling the fiow therethrough.

2. A fuel supply system for an internal combustion engine having a source of fuel and an induction passage comprising a fuel pump, a diaphragm in said fuel pump dividing the interior thereof into first and second chambers, an inlet and an outlet in said first chamber, an air pump having a pumping chamber, a diaphragm in said air pump forming one Wall of said pumping chamber, a rocker arm adapted to be driven by said engine, a

one-way connection between said arm and said fuel pump diaphragm effective to move said fuel pump diaphragm in a fuel intake direction, a one-way connection between said arm and said air pump diaphragm effective to move said air pump diaphragm in an air discharge direction, resilient means in said air and fuel pumps urging said diaphragms in a direction opposite to the movement imparted by said arm through said one-way connections, means connecting the discharge from said air pump to the second chamber of said fuel pump, a calibrated vent in said second chamber, means adapted to connect said fuel pump inlet with said source of fuel, conduit means connecting said fuel pump outlet with said induction passage, and Valve means in said conduit means for controlling the flow therethrough.

3. A fuel supply system for an internal combustion engine having a source of fuel, an induction passage comprising, an engine driven air pump adapted to discharge air at a pressure varying as a function of engine speed, a fuel pump, a diaphragm dividing the interior of said pump into an air chamber and a fuel chamber, means adapted to connect said fuel chamber with said source of fuel, passage means connecting the discharge from said air pump to said air chamber, vent means in said second chamber, a rocker arm adapted to be actuated by said engine, a one-way connection between said arm and diaphragm effective to move said diaphragm in a fuel intake direction, resilient means in said fuel pump urging said diaphragm in a fuel discharge direction, conduit means connecting said fuel chamber to said induction passage, and valve means in said conduit means for controlling the flow therethrough.

4. A fuel supply system for an internal combustion engine having a source of fuel and an induction passage with a throttle therein, comprising a fuel pump, a diaphragm dividing the interior of said fuel pump into an air chamber and a fuel chamber, means driven by said engine for moving said diaphragm in a fuel intake direction, means for generating an air pressure which varies in response to changes in engine speed, a conduit for connecting said last mentioned means to said air chamber whereby air under pressure acts on said diaphragm to move said diaphragm in a fuel discharging direction, means adapted to connect said fuel chamber to said source of fuel, conduit means connecting said fuel chamber to said induction passage, a valve in said conduit means responsive to movement of said throttle for varying the flow through said conduit means, a by-pass connecting said conduit with said source, and valve means in said by-pass for varying the flow therethrough.

No references cited. 

